This fragrant gel polymer system relates to the manufacture of fragrant gels and more specifically to a process of mixing two fragrance components with two polymers. A unique aspect of the system is a reduction in syneresis and in testing requirements for reactivity between components of the system towards becoming a gel.
A variety of gel products are on the market, used mostly for toys, novelties, gifts, window clings, and decorative ornaments. Consumers are particularly attracted by the gel products due to their features of softness, color, and introduction of a scent or fragrance. These features, desired by consumers, are related to the nature of the gel product, which may contain mineral oil among other things. As mineral oil remains liquid at room temperatures, it may separate from the gel product when the gel product contracts slightly during syneresis. Additionally, the careful selection of the composition of gel products has improved related to the dispersion between a scent, or fragrance, and the surface of the gel products for introduction into the atmosphere.
A fragrant gel product results from the cross-linking between a functionalized polymer and a cross-linking agent, both generally liquid in the presence of a single or a multiple part fragrance base. The polymer cross-links in the presence of the fragrance to form a gel which encloses the perfume, or fragrance. The gel can form in a recess in a substrate as an air freshener device, as a block, and the like.
While mixing, the fragrance, polymer, and cross-linking agent forms a practical homogeneous mixture, such a mixture poorly controls the flow of the cross-linking agent in a small volume. For a better gel product, equalizing the flow rates of the different premixes into the final mixing step has had more positive results. Accordingly, the fragrance acquires a formulation by conventional methods and then a portion of the fragrance mixes with the polymer and the remainder of the fragrance mixes with the cross-linking agent. The two mixtures can then be mixed together to form a mixture that gels. As the fragrance remains separated within the two mixtures, the mixture containing the cross-linking agent has a greater volume than the volume of the cross-linking agent alone, and therefore a greater flow rate, more easily controlled.
Though this mixture method works well when the production line starts, the gel produced by the mixture method worsens after the production line has run for a time. The gelling time of the mixture, i.e. the time required for a non-flowing gel to form into a shape, tends to rise over time. This longer forming time causes problems into the manufacturing shift, especially at the end of a shift, on an operating machine. For example, if the gelling time of the mixture increases and exceeds the time that the containers, containing the fragrance elements, occupy the production line, the gel may have partially solidified and may retain some liquid when the containers, or forms, are removed from the production line. This liquid can spill from the forms, or containers, leading to waste of ingredients, disruption of the production line for cleaning, and release of spilled ingredients into the local sewage system.
Fragrances usually contain components which react with either, or both, of the functionalized polymer and the cross-linking agent. The prior art processes have the functionalized polymer and cross-linking agent each mixing with different parts of the fragrance, before the polymer and the cross-linking agent are mixed. Thus, the functionalized polymer and cross-linking agents mix with separate fragrance components, not the same fragrance composition. Instead, the gel product has a final fragrance composition arranged, and different components of the composition are then mixed with the functionalized polymer and with the cross-linking agent. By separating the fragrance components, the issue of incomplete gel formation decreases to a practical extent or even completely ceases.
While the precise ingredients of any particular fragrance often remain trade secrets, the typical classes of ingredients and particularly common ingredients include volatile compounds such as esters, alcohols, aldehydes and ketones. As before, the functionalized polymers and cross-linking agents react with certain fragrance ingredients but not others. The reaction rate may be relatively slow and that does not appear early in a manufacturing shift but, after the fragrance ingredients have been mixed with the functionalized polymer and cross-linking agent for some time, a few hours in many cases, some of the fragrance components will have reacted as a pre-reaction. Alas, these pre-reactions may undesirably affect the fragrance, varying its fragrance over a production run. Furthermore, the pre-reactions consume some of the functionalized polymer and cross-linking agent, thus reducing the concentration of reactive sites of the functionalized polymer and the cross-linking agent later in the production run. The pre-reactions have an often increased setting time using prior art methods and processes.
The functional polymer has one or more functional groups while the cross-linking agent has one or more complimentary functional groups. The mixture of these two provides, in the presence of a fragrance base, a reaction product that encloses the fragrance base in a gel product which then emanates the fragrance to the atmosphere to freshen the air. Suitable functional groups include carboxylic acid, anhydride or acid chloride groups, amines, and alcohols. The functional polymer forms by adding a functional group to any polymer capable of functionalization, or the polymer itself inherently contains functional groups. The functional groups can be pendent on the main chain perhaps with intervening spacer groups or in the main chain. Preferred polymers for functionalization include polyolefins, particularly those derived from mono-olefins or di-olefins containing, at least one vinyl group.
The cross-linking agent generally dissolves in the fragrance base. Suitable cross-linking agents include dihydroxy polybutadiene, alkoxylated primary amines, alkylpropyldiamines having an ethoxylated or propoxylated fatty aliphatic chain, diethanolamine, diethylenetriamine, polyoxyalkylenediamines and alkoxylated primary fatty amines. The cross-linking agent may have one or more diamines or triamines, polyoxyalkylene amines, polyethoxy diamines and triamines, polypropoxy diamines and triamines.
Within the prior art, the fragrance is a mixture of volatile liquid ingredients of natural or synthetic origin. List and descriptions of the ingredients appear in perfumery books, for example in S. Arctander, Perfume and Flavour Chemicals, Montclair, N.J., USA, 1969, and the like. The art of formulating a fragrance begins with devising a base and at least a note having the desired fragrance, generally a common task carried out by a fragrance manufacturer.
Generally, the cross-linking agent reacts with some of the fragrance components, while the functionalized polymer does not appreciably react during a typical production shift. The prior art separates the components of a fragrance into those components of the fragrance which react, or are likely to react, with the cross-linking agent and those components which do not react, or are unlikely to react. Individual fragrance components which do not react with either the functionalized polymer or the cross-linking agent may be mixed with either polymer or cross-linking agent at the discretion of the fragrance manufacturer.